In brief: Re:notch, a Malmö-based energy startup, stores surplus summer solar as heat in the bedrock beneath commercial buildings and delivers it back as heating all winter, cutting heating and cooling costs by 50–75%. Rather than hiring a patent law firm, co-founder and CTO Erik Kayser built the company's startup patent strategy on Lightbringer's AI patent platform: the team experimented with five or six draft approaches at zero cost, ran an IP mining session to map patents and trade secrets, and filed their first patent in weeks. Re:notch's system architecture is now protected by four patents, and Erik's reason for staying has shifted from cost to speed.
Let's meet the founders of the future
In this customer success story, we meet Erik Kayser, co-founder and CTO of Re:notch, a Malmö-based energy startup solving one of clean energy's most stubborn mismatches. A commercial building's roof produces far more solar power than it can use in summer: surplus sold to the grid for next to nothing, while heating is its biggest energy cost, paid at peak prices exactly when the panels give nothing. Re:notch bridges the two seasons: their system turns the summer surplus into heat and charges it into sealed boreholes in the bedrock, where around 80% of it is still waiting six months later. The result is heating and cooling all year round at 50–75% lower cost. Along the way, Erik has built a startup patent strategy that looks nothing like the traditional one, and he has strong opinions about why.
Proven parts, connected in a way that never existed
The individual pieces of Re:notch's system are decades old: borehole thermal storage, ground-source heat pumps, rooftop solar. What never existed is a system connecting them behind the meter, and the component that makes it possible: the Re:notch pipe, a geometry that charges the bedrock roughly ten times faster than conventional ground loops, field-measured with KTH and LTH. Add the dispatch software that decides when to charge, hold and deliver, and you have an invention worth protecting, the system architecture is now covered by a four-patent integration of solar, high-power bedrock storage, heat pump and control.
Getting there, however, meant confronting the traditional patent process, something Erik had no intention of doing on its usual terms.
Two unknowns across the table
Before Re:notch, Erik was a partner at a large management consultancy, where he saw founders struggle with the traditional patent process from the advisor's seat. His diagnosis is blunt: when a founder sits down with a patent attorney, neither side knows what the other knows.
"I'm talking about a topic that I don't know anything about, to someone who doesn't know anything about what I'm talking about. So we have two unknowns, and the cost on that side of the table would immediately start ticking."
Erik Kayser
Co-founder and CTO of Re:notch
That ticking clock shapes everything, Erik explains. Every meeting has to be prepared, every question has to count, and the founder loses the freedom to think out loud. For an early-stage company still figuring out how to protect intellectual property, that's exactly the wrong environment.
Experimenting at zero cost
Working in Lightbringer inverted that dynamic. Anyone can access Lightbringer and start working on their ideas at no cost. You only pay when you decide to file, so instead of rationing billable hours, Erik and his team experimented.
"At the first time, we tried five or six approaches, so we created five or six patent processes," he recalls. "If you were to read them through you'd say, same but different. We got to do this all for free. I am paying nothing for Lightbringer until the day I decide to file a patent. This means, I can play around as much as I like." With a law firm, the meter would have started running on the very first draft.
That freedom to iterate was the big aha moment: the team could explore, compare versions, and let their thinking mature before committing to anything. It also changed how Re:notch thinks about when to file a patent, a decision they could now make on their own timeline rather than an attorney's.
An IP mining session with Lightbringer sharpened this further. In a workshop of about two hours, the team was guided to look at their technology from a different angle, mapping which innovations to patent, which to keep as trade secrets, and how to prioritise given their stage and budget. "Thanks to working inside Lightbringer, our thinking has matured, and our thinking around our problem has matured," Erik says.
An easy filing, and a stronger story for investors
When asked what surprised him most, his answer was short: "It was super easy."
For a startup, the business case extends beyond the filing itself. Investors ask about IP during fundraising, and founders have traditionally waved around the one or two patents they could afford. Re:notch can instead talk confidently about a whole landscape of mined and prioritised innovations. Erik takes the thought one step further:
"It was super easy. For a startup, if I were a VC, I would ask for access to their Lightbringer account, to just go through what they are thinking about. It's a way of fast-tracking."
Erik Kayser
Co-founder and CTO of Re:notch
First it was cost. Now it's speed.
Erik is candid that the initial hurdle was money, the cost of a law firm, in billing and in his own time. But having filed once, his reason for staying has changed. "The first one was: I don't have the money to work with a lawyer. Now: I don't have the time to work with a lawyer," he says. "The IP lawyer is going to slow me down, whereas Lightbringer is going to speed me up."
His advice to other founders weighing an IP strategy for their startup is to flip the question. "You should turn the question around. What value are you looking for when you do IP? And why would a human approach be better than working with an AI tool? You wouldn't write code today without AI."
For Re:notch, the answer is already settled: "My experience with Lightbringer is that it allows me to keep my speed up. It allows me to try out different thoughts at lightning speed. There's no one on the other end, money-wise or time-wise, that I need to relate to. I just do it."
As Re:notch turns the rock under Europe's commercial buildings into seasonal batteries, heating in winter, cooling in summer, powered by each building's own summer surplus, we at Lightbringer are excited to follow their journey, and to keep pace with it.
FAQ
Can you work on a patent for free before filing?
Yes, Lightbringer costs nothing until you decide to file. Re:notch used that to experiment freely, creating five or six draft patent approaches at zero cost and comparing them over time. By the time they committed to filing, most of the thinking was already done, and the filing itself took just a few hours of the team's own time.
What did Re:notch's startup patent strategy look like before filing?
The team drafted five or six experimental patent approaches inside Lightbringer at no cost, then ran an IP mining session to map patentable innovations, trade secrets, and priorities before choosing what to file. Learn more about patent strategy for startups.
Why do startups like Re:notch file patents?
Primarily for fundraising: investors want evidence that a startup owns something worth protecting. A filed patent signals rigour in IP due diligence, without the traditional patent costs of a law firm. New to the process? Start with how to patent an idea.
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